Circuit-closing device for burglar-alarm systems.



PATENTED MAY 14, 1907.

W. H. ROBINS. CIRCUIT CLOSING DEVICE FOR BURGLAR ALARM SYSTEMS.

,APPLIOATION FILED DEO.6,1906.

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UNITED STATES PATENT OFFICE.

WILLIAM H. 'ROBINS, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO AMERI- CAN BANK PROTECTION 00., OF MINNEAPOLIS, MINNESOTA.

CIRCUIT-CLOSING DEVICE FORBUFIGLAR-ALARM SYSTEMS.

- Burglar-Alarm Systems, of which the followmg is a specification.

In the construction of a burglar alarm system it is customary to provide a guard or shield over the gong, to preventit from being tampered with and rendered inoperative by a burglar or" other person. To prevent the ringing of the gong, where access to it directly incr and outer shell,

is prevented by means of a shield or guard, some burglars have ado ted the method of filling the gong and shielrlwithsand, thereby deadening the sound of the hammer, if not entirely preventing its operation. This sand, or other foreign material, can usually be filled in between the shield and thegong ithout bridging the space between the inand thereby closing the alarm circuit, and, consequently, it hasbeen fiyund desirable and I have made it the object of my present invention to rovide a device preferably located below t e ong near th bottom of the inner shell of t e shield, wl i when sand or other foreign material is poured irito the shield, will be actuated to close the alarm circuit.

The invention consists, generally,fin a de vice arranged to be actuated by the weight of the foreign material fillediin between the gong and shield to closea local circuit and release the drop, which in turnwhen operated will close the alarm circuit a'nd sound the gong before any considerable amount of foreign material can be inserted into the shield. 1

In the accom anying drawings forming part of this specification, Figure 1 is a vertical sectional view through the shieldilhis- .trating the mechanism 'in'closed thereby. Fig. 2 is a similar sectional view taken on a section line substantially at right angles to thesection line of Fig. 1. .Figf3 is a'plan view of the circuit-closing device. Fig. 4 is alongitudinal sectional view of the same.

' In the drawing,2 represents a backplate whereon the shield, consisting of an-outer shell 3 and an inner shell 4 separated by an air space but connected suitable insulated screws '5, is-secured. A hollow stud 6is con-o nected, with the Specification of Letters Patent. Application filed December .6, 1905; Serial No. 290,569-

closed through the magnet 10.

Patented May 14, 1907.

through the inner one and the base 2. A gong 7-is mounted on the said base and has a suitable hammer 8 connected with the arma ture 9 that is actuated when the circuit is is mounted on a suitable frame 11 and in cir- The magnet cuit therewith, and contact springs 12 are carried by said armature and are adapted-to engage a contact screw 13 which is mounted in the said frame and insulated therefrom and irggircuit with a post 14, to which a wire 15 is attached. Th'

1s wire runs to a battery B and from thence with a frame 17 of a circuit closer 18, which I will designate as the primary one. The contact point 19 of this circuit closer, which to a.p0st 16 connected forms the subject matter of a companion application herewith, is connected by a wire 20 with a post 21 on the frame 11, and said post has a connection 22 through the magnet 10 with the said frame. Below the gong 7 a box 23 is arranged containing a chamber 24, wherein a spoon-shaped secondary circuitclosing device 25 is centrally pivoted upon a bracket 26. A cover 27 is rovided on said box having any opening 28 directly. above the bowl of the circuit closer. The handle of the circuit closer has a slot 29 with a weight device 30 adjustably mounted thereon and adapted to be moved back and forth in said slot until it barely'overbalances the weight of.

the bowl and causes it to swing 'u ward agamst the boX cover, as indicated in ig. 4. A contact post 31 is provided beneath the bowl of the circuit closer in position to be en-' gagedthereby when any foreign material falls through the hole 28 into the bowl and depresses the same. 'A wire 32Lleadsfron1 the post 31 to the l'rame 11. A second post'33 is provided in the bottom of the lion in circuit with the bracket 26-. and connctedbyvthe wire 34 with a'contact post '35 on. the inner shell of the shield. A wire 36 the post to the cuit closer 18.

The local circuit is tween the bowl of closer and the. post 31.

extends from magnets of the primary cirnormally broken be;

When, however, this bowl is depressed the circuit will be closed ."betweenthepostsBl and 33 through the circuit closer irame 17 to release the dro and close, the'nrainor alarm ClICllltw The c osing.

:ofthis. local circuit will take place whenever outer. shell, and, projects any-foreign material, such as sand. is filled the secondary f, circuit ner shell of the shield, as the sand flowing down into the bowl of the spoon-shaped circuit closer will immediately depress the same to contact with the post 31 and close the circuit. Normally, however, the weight ofthe device 30 will be sufiicieut to hold the bowl of the circuit closer out of Contact with the 'post 31 The secondary circuit closer will also be operated if any material in liquid form'is deposited in the space inclosed by the inner shell of the shield; and it-will be impossible for a'burglar, or any unauthorized-person,

to tamper with the system and attempt to render the gong inoperative, by inclosing it witha foreign material without actuating the s oon-shaped circuitcloser and closing the a arm circuit. I

It is desirable in aidevice ofthis kind to provide means for closing the alarm circuit, should anattem t be made to pierce the shield and there y momentarily establish a metallic short circuit between them. With this end in view I provide a wire 37 connectin the stud 6 with the wire 15. This wire 15 t ough the circuit closer and the wire 36 is connected with the post 35 on the inner shell of the shield, and the stud 6, as heretofore stated, is connected with the outer shell of the shield; and, conse uently, any attem t to bore through the s 'eld with a tool oi: any kind will form a metallic bridge or connection between the inner and outer shell and close the localcircuit through the primary circuit closer 18 and release the drop to close the alarm circuit. v

I claim as my invention:

. 1. The-combination with an alarm circuit having a gong, of a shield inclosing said gong, a circuit closer arranged in the lower part of said shield and having a suitable receptacle, said circuit closer being connected with said alarm circuit-and arranged when actuated, to close the same, and the inner walls of said shieldbeing' curved and adapted to direct sand or foreign material deposited in the shield into 'said receptacle, substantially as described.

2. The combination, with an alarm circuit having a. gong, of a shield inclosing said gong, a circuit closer-arranged in the lower part of said shield and having a suitable receptacle, said circuit closer being connected with said alarm circuit and arranged when actuatedto close the same, and the inner walls of said shield being arranged to direct sand or foreign material deposited in the-shield into said receptacle.

,3. The combination, with an alarm circuit having a gong, of a shield inclosing said gong, a circuit closer pivoted at a point in termediate to its ends and having a bowl 'or depression in one end and a counter balance on its other end, and connected with said alarm circuit, the bowl of said circuit closing device belng adapted to receive sand or any foreign material deposited in the shield, and

a contact point arranged beneath the said bowl to be engaged thereby toclose sald alarm circuit.

4T The combination, with an alarm circuit having a gong, of a shield inclosing said gong, a tilting circuit closing device central y pivoted in said shield and connected with said alarm circuit and having a bowl or receptacle adapted to'receive sand and foreign material deposited in said shield, a counter balance mounted on the handle portion of said-circuit closing device and normally balancing the weight of said bowl, and a contact point connected with said alarm circuit and located beneath said bowl and engaged thereby when said bowl isdepressed by the weight ofthe material therein.

5. The combination, with an alarm circuit having a gong," of a shield inclosing said gong, a circuit closing device centrally pivoted in said shield and connected with said alarm circuit, one end of said circuit closing device having a receptacle adapted to receive sand and foreign material deposited in said shield, and the other end of said circuit closing device having a slot and a counter bal ance weight mounted therein and adapted to be adjusted to balance the weight of said receptacle, and a contact point connected with sald alarm circuit and located in the path of said receptacle, whereby depression of the same under the weight of the foreign material will close the said alarm circuit.

6. The combination, with'an alarm circuit having a gong, of a shield inclosing said gong, a box arranged in the lower part of said shield and having a chamber or recess, and a plate arranged over said chamber and provided with an opening leading to said recess, a tilting circuit closing device arranged in said chamber and having a bowl adapted to receive sand or foreign material deposited in said shield, and a contact point connected with said alarm circuit and located in the path of said bowl, whereby the alarm circuit will be closed when the bowl has tilted a predetermined distance. I

In witness whereof, I have hereunto set my hand this 22nd day of November 1905. WILLIAM H. ROBINS. Witnesses:

RICHARD PAUL, C. MAONAMARA. 

